Threading-die holder



Sept. 19, 1950 F. H. WARREN THREADING-DIE HOLDER 2 Sheets-Sheet 1 Filed March 8, 1946 Wm. M v al/4 M 22 yum e. W M M #MMH w 6, M Q m P 1950 F. H. WARREN 2,522,655

THREADING-DIE HOLDER Filed March 8, 1945 2 Sheets-Sheet 2 i dgz l T E I gfgzglf 38 30 22 21 3L; 31 AL hue/22 0f Patented Sept. 19, 1950 THREADING-DIE HOLDER Frederick H. Warren, Waterbury, Conn, assignor to Greenfield Tap and Die Corporation, Greenfield, Mass., a corporation of Massachusetts Application March 8, 1946, Serial No. 653,222

2 Claims.

that the friction of the rotary sliding action of the adjusting-sleeve on the threading-prongs, flexes the threading-prongs sidewise so that the helix angle of the thread-cutting teeth of the threading-prongs is altered, so that the teeth out a distorted form of thread, inasmuch as the trailing edges of the cutting-teeth do not track properly with the advanced edges of their respective cutting-teeth, thus decreasing the accuracy of the lead or pitch of the thread that is cut on an article to be threaded. This distortion also brings about another serious defect when the threading-die is being employed for cutting a straight thread, in that the distortion of the threading-prongs results in cutting a thread having a substantial taper instead of being truly straight.

One object of the present invention, therefore, is to provide an improved threading-die holder which will have a true radial adjusting action without any sidewise or circumferential distorting action.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the description and claims, the various parts and steps are identified by specific terms for convenience, but they are intended to be as generic in their application as the prior art will permit.

In the accompanying drawings forming part of the present disclosure, in which one way of carrying out the invention is shown for illustrative purposes:

Fig. 1 is a side elevation illustrating one em-, bodiment made in accordance with the present invention;

Fig. 2 is a right-end elevation of Fig. 1;

Fig. 3 is a left-end elevation of Fig. 1;

Fig. 4 is a longitudinal vertical central sectional view on line 4-4 of Fig. 2;

Fig. 5 is a transverse sectional view on line 55 of Fig. 4;

Fig. 6 is a transverse sectional View on line 6-40 of Fig. 4;

Fig. 7 is a fragmental perspective view partly in section, of the body including the shank and head;

Fig. 8 is a fragmental perspective view of the operating-collar;

Fig. 9 is a fragmental perspective view of the lockingcollar;

Fig. 10 is a perspective view of an acorn threading-die; and

Fig. 11 is a fragmental perspective view of the adjusting-sleeve.

Referring to the drawings showing the particular form of the invention chosen for illustration therein, the threading-die holder includes a body 2| which, in turn, includes a shank 22 and a head 23. The head 23 has a stem 24 slidable in the cylindrical bore 25 of the shank 22, which stem 24 has a bushing 26 secured thereon by a screw 21. The bushing '26 is slidable in the enlarged bore 28 of the body 22. A

coil-spring 29 is engaged between the bushing 28 and the annular shoulder 30 so as to yieldingly hold the stem 24 in the position illustrated in Fig. 4, for permitting it to move longitudinally to the right for a limited distance against the action of the spring 29.

The head 23 has rearwardly-extending coupling-extension means 3! in the form of a parallel-sided key at its rear end, which is longitudinally slidable in the coupling-recess means 32 at the forward end of the shank 22. The coupling-extension means 3! has its opposite ends extending beyond the circumference of the shank 22 and provided with interrupted thread-portions 33 .and 34 adapted to threadedly receive the screw-threaded interior 35 of the lockingcollar 36.

The head 23 has forwardly-extending coupling-extensions 3'! and 38 in the form of pins extending forwardly into coupling-recesses 39 and 40 formed at the rear end of the threadingdie 41. The threading-die M is of the well known acorn type having a plurality of integral forwardly-extending flexible threadingprongs or arms 42 each of which is provided with a plurality of thread-cutting teeth 43. Each prong 42 has a conical surface-portion 44 adapted to be engaged by a conical surface d5 of a dieadjusting sleeve 46 which has a cylindrical bore ll having a neat sliding fit over the cylindrical outer surface d8 of the head 23. A couplingpin 49 extends radially inward beyond thecylindrical surface 47, to slidingly engage the longitudinal slot 50 in the outer portion of the head 23 to guide the adjusting-sleeve longitudinally forwardly and rearwardly and prevent relative rotation between the parts 23 and 46.

The cup-shaped operating-collar M has a central aperture 52 through its rear or bottom wall 53 to permit the collar i to be slid over the shank 22 and threaded portions 33 and 34, to permit of bringing the bottom or rear wall 53 against the rear face 54 of the head 23. The operating-collar 5| has interior threads 55 threadedly engageable with the exterior threads 56 of the adjusting-sleeve 46.

Operation from the right end thereof, and assuming the locking-collar 35 to have been rotated clockwise to unscrew it and move it rearwardly to bring it spaced away from, and out of locking engagement with the operating-collar 5!, 1f it is now desired to adjust the threading-prongs 52 by flexing or springing them radially inward, the operating-collar 5! is to be rotated counterclockwise,

which will draw or pull the adjusting-sleeve 46 longitudinally rearwardly but not rotatably, due to the pin 49 sliding along in the long1tud1nal groove 55), to thus cause the conical surface 4b of the sleeve 46 to have a camming action upon the conical surface-portions i i of th prongs 32, to thus spring the prongs radially inward for adjustment of the diameter of the thread to be out. After the operating-collar 5i has been rotated sufficiently to bring about the desired degree of adjustment of the threading-prongs t2, th locking-collar 35 is to be rotated counterclockwise until it jams against the rear or end wall 53 of the operating-collar 5!, to thuslock the operating-collar 5| against any rotational movement.

' It will thus be seen that inasmuch as the adjusting-sleeve 46 moves only in a longitudinal direction while springing the prongs 42 inward, and does not have any rotational movement, there can be no circumferential or sidewise springing of the threading-prongs 42.

Thus applicants improved threading-die holder avoids the defects of the prior art construction which owing to the circumferential or sidewise distortion of the threading-prongs, alters the helix angle to thus produce a thread of distorted form, in which the trailing edge of each cuttingtooth does not track properly with the advance edge of such cutting-tooth, and th altered helix angle objectionably affects the accuracy of the lead or pitch of the thread. Also, when it is desired to cut a straight thread, applicants improved construction permits of obtaining much nearer to a true straight thread than is possible with the previously described prior art construction.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An adjustable threading-tool including in combination: a body having a shank and a head; said shank having a recess at its front end; said head being of greater diameter than the diameter of said shank and having a key at its rear end, which key extends into said recess and prevents relative rotation but permits relative longitudinal sliding movement between said shank and said head; said key having its opposite radial ends extending beyond said shank, and the opposite end-surfaces of said ends .being provided with screw threads; a threading-die having an integral, annularly-continuous rear end-portion in relatively non-rotatable engagement with said head, and having a plurality of flexible threading-prongs integral with and extending forwardly from said rear end-portion; a die-adjusting sleeve surrounding said threading-die, and non-rotatably but longitudinally slidably engaging said head, and engageable with the forward end-portions of said threading-prongs to flex said prongs toward the axis of said threading-die when said die-adjusting sleeve is moved longitudinally rearwardly, and having an integral, annularly-continuous rear-portion provided with screw threads; an operating-co1lar having an integral, annularlycontinuous forward-portion provided with screw threads in threaded engagement with the said screw threads of said die-adjusting sleeve, and having an apertured end-wall engageable with said head to limit the forward movement of said operating-collar relative to said head, rotation of said operating-collar in one direction causing said adjusting-sleeve to move longitudinally rearwardly, and rotation in the opposite direction permitting said adjusting-sleeve to move longitudinally forwardly; and a locking-collar threadedly engaged with the threads of said key-ends to lock said operating-collar against rotation relatively to said head.

2. An adjustable threading-tool including in combination: a body having a shank and a head; said shank having a recess at its front end; said head being of greater diameter than the diameter of said shank and having a key at its rear end, which key extends into said recess and prevents relative rotation but permits relative longitudinal sliding movement between said shank and said head; said key having its opposite radial ends extending beyond said shank, and the opposite end-surfaces of said ends being provided with screw threads; a threading-die having an integral, annularly-continuous rear end-portion in relatively non-rotatable engagement with said head, and having a plurality of flexible threading-prongs integral with and extending forwardly from said rear end-portion; a die-adjusting sleeve surrounding said threading-die; and non-rotatably but longitudinally slidably engaging said head, and engageable with the forward end-portions of said threading-prongs to flex said prongs toward the axis of said threading-die when said die-adjusting sleeve is moved longitudinally rearwardly, and having an integral, annularly-continuous rear-portion provided with screw threads; an operating-collar having an aperture therethrough and an integral, annularly-continuous forward-portion provided with screw threads in threaded engagement with the said screw threads of said die-adjusting sleeve, and having means engageable with said head to limit the forward movement of said operating-collar relative to said head, rotation of said operating-collar in one direction causing said adjusting-sleeve to 5 move longitudinally rearwardly, and rotation in UNITED STATES PATENTS the opposite direction permitting said adjusting- Number Name Date sleeve to move longitudinally forwardly; and a 1 456 805 Koontz May 29 1923 locking-cellar threadedly engaged with the 2063980 Bruce 1936 threads of said key-ends to lock said operating- 2152711 slotta 5 1939 collar against rotation relatively to said head. 2 5 T FREDERICK H. W ARREN. ,2 8,68 Bemamm Jan. 14, 1941 I I FOREIGN PATENTS REFERENCES CITED Y Number Country Date The following references are of record in the 10 115,320 Germany Dec. 15, 1900 file of this patent: 650,514 France Sept. 24, 1928 

